In [1]}, the stability and economic performance of the EMPC with zone tracking framework were studied without considering process uncertainty. In this work, we extend [1]} to consider constrained nonlinear systems subject to unmeasured but bounded disturbances. Instead of tracking the original target zone, we propose to track a robust control invariant set within the target zone so that once the system state enters the invariant zone, it will not exit the target zone anymore. The proposed design can ensure that the zone tracking objective is achieved in finite steps and at the same time optimizes the economic performance. It is found that in the presence of uncertainty, the economic performance of EMPC not only depends on the optimal steady state but also the size of the tracked zone. To take this into account, we introduce the notion of risk factor in the controller design. The risk factor determines the conservativeness of the controller and provides a way to tune the EMPC for better economic performance. An algorithm to determine the zone integrating the risk factor is also proposed. A nonlinear chemical example is presented to demonstrate the performance of the proposed formulation. We note that the extension of [1]} to this work is not a trivial task. The contributions of this work include:
